Well, even cheap storage isn’t anything for me to laugh at these days.
Also, check the bitrate of your files. Depending on what you’re using, converting to ProRes may be unnecessary. You might only need ProRes LT, or if the source is from H.264 you could likely edit with that if you’re using Premiere Pro or Final Cut Pro X. Avid would need ProRes or DNxHD/XR, but I doubt anyone is using that. There’s no added quality in making the files unnecessarily larger.